yamaha c3 scooter fuel pump help needed.

Discussion in 'Battle Scooters' started by Ren20, Mar 12, 2013.

  1. Ren20

    Ren20 Finding Touge

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    Jan 25, 2012
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    I am trying to help my uncle to fix his yamaha c3.
    The scooter doesn't get any fuel. So we bought a replacement fuel pump. We install the new one But ignition doesn't prime the new fuel pump. We can prime it by connecting battery directly.

    We are new to this Efi scooter. Any idea where we should look on the circuit?
    #1
  2. Motovista

    Motovista Parts is Parts

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    Did you bench test the old pump before ordering a new one? Is the new one OEM or aftermarket? If it's a new OEM pump and installing it didn't fix the problem, the old one is probably fine. I see more relays fail than pumps, and that's where I would suggest you look next.
    #2
  3. fullmetalscooter

    fullmetalscooter Let me take this duck off

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    Hold on is it 2007? then free dealer repair because of recall that year on c3 for fuel pumps.
    #3
  4. JerryH

    JerryH Banned

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    First year C3s did have a fuel pump recall, same as the Zuma 125.

    As far as the new pump not working, there is a lot more to a fuel pump on a fuel injected engine than just the pump itself. The pump is controlled by the ECU, a mega expensive and easily damaged part. This is where the problems arise on fuel injected engines. It's not the pump or the injector most of the time, it's either one of the sensors (hopefully) or the computer that controls everything. Either way it is not a job for a home mechanic. Geez I love carbs.

    But take it to a dealer and let them check it. Point out the recall. Unfortunately most places will not give refunds on electrical parts.
    #4
  5. Ren20

    Ren20 Finding Touge

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    It's a 2007. He decided to give an aftermarket kit a try. It was 40 dollars. Bringing it to dealer would cost us too much time than good.

    If we can figure this out in garage great. If not, then we can think about dealer. After all, there is only so many wires and screws on this little scoot.
    #5
  6. Warney

    Warney Been here awhile

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    Moped Medic's diagnosis is most likely correct, using a test light make sure the fuel pump relay is getting power when the ignition is switched on. If it is, then test the output to the fuel pump. The ECU controls power to the relay, which powers the pump. Very doubtful the ECU is fried.
    #6
  7. k-moe

    k-moe Long timer

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    I've worked on fuel injected engines for 25 years...not once have I found a failed ECU. Fuel pumps fail much more often than either injectors or an ECU. The only control that the C3 ECU has over the fuel pump is signaling the relay to start the pump up when the ignition is turned on. The only sensor connected to the fuel pump is the thermal overload relay that is built into the pump.


    Ren20:

    1. verify that electricity is reaching the pump/ verify that the fuel pump relay is working.

    2. verify that your battery is fully charged.

    3. Verify that the fuel pump fuse isn't blown (could have happened if you did not disconnect the battery before removing the old pump).

    I recall that Yamaha did a voluntary recall to remedy a seal on the fuel pump that was causing fuel vapor to be vented without passing into the evap canister, but not for pump failure. There is a recall for the crankshaft though: http://www-odi.nhtsa.dot.gov/owners/SearchResults.action;jsessionid=pkdKRBfXsK1vfQGY4yl8yTPDS6lGBksFRYptZkyysw5TCCLH2VW9!1756941731


    You also might follow the recommendation found here: http://www.zumaforums.net/phpBB3/viewtopic.php?f=48&t=4114
    #7